Slide switch cutover device contactor

ABSTRACT

The present invention relates to a switching device; and more particularly relates to a switching device that comprises a switching pad that makes and breaks electrical circuits as the switching device is moved from one position to another. The disclosure teaches how such a switching pad may be mounted in a freely floating manner, so that it provides optimal electrical contact at all times, with minimal danger of changing pressure and/or accumulation of corrosion.

nited States Patent Garrett et a1.

SLIDE SWITCH CUTOVER DEVICE CONTACTOR Inventors: Jim C. Garrett, 6331 Vera Crest Drive, Long Beach, Calif.90804; Robert H. Johnson, 4764 M La Villa Marina, Marina Del Ray, Calif. 90291; Jack Shelton, 810 Rancho Drive, Long Beach, Calif. 90804; Louis P. Labarge, Irvine, Calif.

said Garret, Johnson and Shelton, by said LaBarge Filed: Nov. 16, 1971 Appl. No.: 199,243

Assignee:

Us. (:1. 200/16 (3, 200/166 BE Int. Cl. H01h 15/06 Field Of Search 200/1 c, 16 D, 166 BE,

References Cited UNITED STATES PATENTS 6/1972 Schadow.... 200 16 D x 9 1972 Otterlei 200/16 0 June 19, 1973 3,399,282 8/1968 Nagashima et a1. 200/16 D 3,150,240 9/1964 Voss 200/16 C X 3,209,088 9/1965 Wanlass 200/16 C FOREIGN PATENTS OR APPLICATIONS 565,859 11/1944 Great Britain 200/166 BF 1,135,989 9/1962 Germany 200/16 C 1,415,549 9/1965 France Primary ExaminerJ. R. Scott Attorney-Albert L. Gabriel 5? ABSTRACT The present invention relates to a switching device; and more particularly relates to a switching device that comprises a switching pad that makes and breaks electrical circuits as the switching device is moved from one position to another. The disclosure teaches how such a switching pad may be mounted in a freely floating manner, so that it provides optimal electrical contact at all times, with minimal danger of changing pressure and/or accumulation of corrosion.

6 Claims, 7 Drawing Figures Patented June 19, 1973 3,740,500

mvsmoxs, J/M a wear? 205597 /1.. JOHNSON Z6 0746K .swa ro/v wxw ArraPM-ry I SLIDE SWITCH CUTOVER DEVICE CONTACTOR BACKGROUND OF THE INVENTION In the use of telephone office equipment, a so-called cutover procedure is used for trunk line rearrangeity of circuits terminating at selected electrical terminals of the cutover block. Such a cutover block may have literally hundreds of electrical terminals projecting in rows from one of its surfaces, and it is the practice to insert elongated cutover devices at selected rows of terminals that project from the one edge of the cutover block. If the cutover procedure using the cutover device does not work correctly, the'cutover devices are removed, and suitable repairs are made.

In this way the cutover operation is pretested, before making more permanent connections,if these are desirable.

Unfortunately,prior art cutover devices are not completely satisfactory. When these devices are new, they tend to produce unequal mechanical pressure, and this results in unequal electrical contact leading to unsatisfactory flow of electricity and unreliable results.

As the prior art cutover devices age, their springiness tends to decrease in an uneven manner, so that the resultant electrical contact becomes even less reliable, and their results become even more undependable.

OBJECTS AND DRAWINGS It is therefore the principal object of the present invention to provide an improved switching device.

It is another object of the present invention to provide an improved cutover device.

It is still another object of the present invention to provide an improved cutover'device that provides improved electrical contact. 7

It is a further object of the present invention to provide an improved cutover device that provides more reliable results.

It is a still further object of the present invention to provide an improved cutover device that has a longer useful life. I

The attainment of these objects and others will be realized from a study of the following specification, taken in connection with the drawings, of which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a cutover device in a first operative position;

FIG. 2 is a view similar to FIG. 1, showing a cutover device in a second operative position;

FIG. 3 is an exploded, partial, perspective view of the improved cutover device;

FIG. 4 is a fragmentary axial sectional view taken on the line 44 in FIG. 5;

FIG. 5 is a pictorial perspective view of the improved cutover device;

FIG. 6 is a side elevational view of one form of switching pad that may be employed in the invention; and

FIG. 7 is perspective view illustrating a longitudinally compacted form of cutover device according to the invention.

SYNOPSIS The disclosed cutover device is made in such a way that it separates the electrical function from the resilient function, thus permitting the use of two different materials that may be selected for their own particular purposes, rather than using materials that are a compromise. The free-floating characteristic of the disclosed cutover device additionally provides a balanced force arrangement that ensures a more even distribution of the mechanical pressure, and thus produces an improved electrical operation.

INTRODUCTION Use of the Cutover Device The cutover device and its use will be better understood from the schematic representations of FIG. 1 and 2. These figures show a plurality of sets of electrical terminals, such as 10a, 10b, 10c; 11a, 11b, 11c; and 12, 12b, and 120 for a first circuit, as they may appear projecting from a cutover block (not shown), as discussed above the circuitry associated with the electrical terminals having been omitted for clarity. Other sets of electrical terminals 13a, 13b, 13c; 14a, 14b, 14c; and 15a, 15b, 15c for a second circuit are shown as they might appear projecting from the cutover block in spaced, aligned relation to the respective first circuit terminals. As suggested above, there may be a large number of such sets of electrical terminals associated with a cutover block.

The schematic illustrations of FIG. 1 and 2 indicate, for ease of explanation, an oversimplified cutover device 18 that is formed into a rectangularly shaped bar or body 19 of insulating material, such as styrene or other suitable plastic, body 19 having a plurality of separate electrically insulated switching pads 20a, 20b, and 200 that are visible on the front surface of the body 19, other such switching pads being positioned on the back surface of body 19, and therefore not being visible in FIG. 1. Cutover device 18 is known as a double row cutover device since it is adapted to operate on two rows of electrical terminals;single row cutover devices also being used.

In FIG. 1, cutover device 18 is shown to be in a first operative position wherein its switching pads 20 are positioned to complete electrical circuits between respective terminals a and b of the various sets of electrical terminals. It should be noted that in this first position of the cutover device 18, the electrical terminals 0 are unconnected.

As part of the cutover operation, the cutover device 18 is moved (rightward in this illustration) so that it assumes the second operative position as indicated in FIG. 2. Here, it will be seen that the switching pads 20 no longer complete the electrical circuits between electrical terminals a and b; but now, they complete the electrical circuits between respective electrical terminals b and c of respective sets of electrical terminals now leaving electrical terminals a unconnected.

In this way, a suitably designed cutover device 18 may be used for cutting in or cutting out just one set of electrical terminals; or may be used cutting in or cutting out a plurality of sets of electrical terminals.

The cutover device 18 provides an easy,rapid switching operation, the result of which may be quickly checked for operativeness. If everything is satisfactory, then hard wiring may then be installed if desired; alternatively, if something is unsatisfactory, the initial operative position of the cutover device 18 is easily reestablished by moving the cutover device 18 back to the left as illustrated in FIGS. 1 and 2.

Problems of the Cutover Device It will be realized that if the mechanical contact between any of the switching pads 20 and any of the electrical terminals a-10c is faulty, an erroneous electrical result will be produced; and, in cases of such erroneous results, an enormous amount of time may be wasted in trouble shootingg the circuitry, and in making repairs when in actuality, the circuits may have been satisfactory in the first place. It is therefore extremely important that cutover device 18 have its switching pads 20 constructed in such a way that good electrical contact is always assured.

The prior art technique in cutover devices for achieving electrical contact was to form the switching pads 20 of a springy material, such as beryllium copper, and to configurate this material into a leaf-type spring that was riveted at one end in a so-called cantilever arrangement. This prior art cantilever construction produced a switching pad having one end that was quite flexible, whereas its other end tended to be quite rigid. Therefore, this prior art leaf-like switching pad configuration did not provide equal pressure on the electrical terminals l0al5c, resulting in the following disadvantages. Too weak a spring pressure did not produce satisfactory mechanical, and hence electrical, .contact, and, moreover, permitted the buildup of corrosion on the contact surfaces since there was not enough pressure and friction to abrade off the corrosion and to polish the contact surfaces. On the other hand, too great a spring pressure caused excessive wear, and caused the switching pad to gradually flatten out, and to thus eventually reduce its overall pressure'on the electrical terminals.

In an attempt to achieve more uniform pressure over its entire face, the leaf spring was bent in various ways. Unfortunately, this prior art approach was not completely satisfactory either.

Because of the partially rigid, partially flexible spring characteristic, the spring pressure produced by the prior art switching pads generally applies more force at one end thereof than it does at its other end, thus producing an unbalanced contacting force condition.

Therefore, to assure that they would be operative, the prior art cutover devices generally had to be carefully inspected before each use, and before every troubleshooting attempt. Not only was this a burdensome chore, but it also meant that a substantial inventory of replacement cutover devices had to be readily available at every location where they might possibly be needed.

DESCRIPTION Basic Concept The basic concept of the present invention will be understood from FIG. 3, which shows an exploded, partial, cutaway view of the improved cutover device 25. This is shownin an orientation that, for purposes of clarity, has been rotated 90 relative to those cutover devices shown in FIGS. 1 and 2, so that the thickness dimension of the improved cutover device 25 is now vertical, rather than being horizontal.

The improved cutover device 25, as will be shown later, has its body 26 formed of three component parts that are sandwiched together to make the composite body 26. The center core component 27 has a plurality (only one being shown in FIG. 3) of rectangular recesses 28 that extend about one-third of the way through the thickness of core portion 27. A centrally positioned post 30 of each rectangular recess has an axial length that makes its top substantially flush with the top of the core portion 27, post 30 having a diameter that is somewhat smaller than the width of recess 28 the reason for this will become more apparent from a subsequent explanation.

A similar recess 28 (not shown) is located on the back side of core portion 27, to thus produce a pair of back-to-back recesses, and two additional back-toback pairs of such recesses are longitudinally spaced along the core portion 27 in order to provide three pairs of switching pads as indicated in FIGS. 1 and 2.

The exploded view of FIG. 3 indicates a helical spring 32 having a diameter that is dimensioned to encircle post 30, and to fit within the width of the rectangular recess 28. Helical spring 32 has a longitudinal free length that makes it normally extend substantially above the top of post 30, and this feature will be discussed later.

The exploded view of FIG. 3 also indicates a switching pad 33 formed into a roughly bridge-shaped configuration having a generally flat contacting surface 34, sloping sides 35, and end tabs 36.

The exploded view of FIG. 3 further indicates a pair of cover strips 38 that form the sides of the composite body 26. Each cover strip 38 has a rectangular cutout 39 that has the same width as the recess 28, but has a slightly shorter longitudinal length. Cutout 39 is positioned to fit over recess 28 in a centered manner, for reasons to be discussed later.

The bridge-like switching pad 33 is slightly shorter and narrower than the recess 29, so that if the spring 32 were not in position, the switching pad 28 could be dropped into, and would fit loosely, in recess 28, and would come to rest with its end tabs 36 resting on the bottomof the recess 28.

Operation In actuality, the helical spring 32 will have been positioned to encircle the post 31, so that the switching pad 33, rather than sitting on the bottom of recess 28, will actually be held above the top of post 30 by the action of the spring 32, which will in turn be held in position by the post 30.

Due to the fact that the switching pad 33 is shorter and narrower than the rectangular recess 28, and that the switching pad 33 is not attached to the composite body 26 in any way, the spring 32 causes the switching pad 33 to assume a free floating mode, the generally flat contact surface 34 projecting upward through the rectangular cutout 39 of the cover strip 38. The extent of this projection is controlled by the engagement of the end pads 36 with the cover strip 38, the helical spring 32, producing a pre-biased pressure when contact is made.

FIG. 4 shows an axial sectional view of a portion of the disclosed cutover device, illustrating the elements discussed above. FIG. 4 shows the core portion 27 and the two back-to-back rectangular recesses 28, each having its own individual post 30; and shows the upper and lower cover plates 38.

The upper part of FIG. 4 shows the assembly in its relaxed mode, the expanded spring 32 being illustrated as holding the switching pad 33 in its maximal freefloating position being held captive by the end tabs 36.

The lower part of FIG..4 shows the assembly in its compressed mode, the compressed spring 32 being illustrated as holding the free-floating switching pad 33 against a pair of electrical terminals a and 10b.

The symmetrical structure and the electrical positioning of spring 32 urge the switching pad 33 outward in a unitized manner so that the switching pad 33 applies substantially identical pressure against both electrical terminals 10a and 10b, thus providing a balanced pressure free-floating contact with the electrical terminals.

It will be noted that transverse movement of the switching pad 33 is limited by the longitudinal sides of the rectangular recess and/or by the longitudinal sides of the rectangular cutout. Similarly, the longitudinal movement of the switching pad is limited by the transverse sides of the rectangular recess. In a like manner, the axial in-and-out movement of the free-floating switching pad is limited by abutment of the end tabs of the switching pad against the cover plate.

For the reasons discussed above, the disclosed switching pad does not need the inherent springiness of the prior art switching pad, and it may thus be made of a material that is selected primarily for its electrical conductivity characteristics. Moreover, since the helical spring does not carry any electrical current, it may be formed of a material that is selected primarily for its spring characteristicsln this way, the dual functions of the prior art switching pad have been separated, thus permitting an improved product wherein each of the separated functions is better accomplished. Operational Embodiments FIG. 5 shows a pictorial partially cut away view of the disclosed cutover device 25. It will be noted that this illustration shows a hole 40, and it will be realized that when a plurality of such cutover devices are to be used, the holes will be aligned with each other. In order to provide simultaneous action, if this is desired, a rod or dowel may be inserted through all the apertures 40 of the aligned cutover devices, so that the rod may simultaneously move all of the aligned cutover devices.

It will also be noted that in FIG. 5, the cutover device includes a locking ear 41, so that when the cutover device 25 is moved to the desired extent, the locking car may be engaged by a suitable stop strip (not shown), that holds the cutover device in its desired position.

It will additionally be noted that FIG. 5 illustrates the cutover device as having an enlarged head 44, this enlargement permitting a finger grip for manipulating the cutover device when withdrawal movement of a single cutover device is desirable. Alternatively, a rod or hook may be engaged into the aperture 40 for achieving such movement.

Since the cutover device is required to carry only a small amount of electrical current, at a very low volttrical contact points between the switching pad 33 and the electrical terminals, this dimple configuration having the advantage that the mechanical pressure may be made quite high to facilitate the desired flow of electricity, and to provide a wiping action that removes accumulated corrosion during use.

The cover strips 38 may be affixed to the core portion 27 in any desired manner, i.e., heat fusion, adhesives, riveting, bolting, or the like. While a suitable jig may be used to hold together the three portions (38,

27, 38) of the composite body 26 of the cutover device 25, it may be desirable to use an indexing pinhole arrangement as indicated in FIG. 5. Here, a plurality of indexing pins 46 in the cover strip 38 are positioned to fit into a like plurality of indexing holes 47 in the core portion 27 of the composite body 26.

FIG. 6 illustrates a contacting pad 48 having a presently preferred configuration, wherein the exposed contacting portion is slightly centrally depressed in a V configuration so as to compensate for the tendency of the helical spring to bow the pad outwardly, assuring that contact will be made through the dimples.

FIG. 7 illustrates a longitudinally compacted form of the invention generally designated 49, which has the enlarged head 50 laterally offset from the body thereof. The head 50 has rod-receiving hold 51 therethrough for gang switching of a plurality of the cutover devices 49, and has its inner edge 52 knurled or serrated to faage, a large area current-carrying conducting surface is not necessaryin most cases. For this reason, the outer surface of switching pads 33 may be provided with a plurality of dimples" 45 that serve as the actual eleccilitate withdrawal.

SUMMARY The present invention provides many advantages over prior art cutover devices. First of all, it is ideal for cutovers, for trunkline rearrangements, for number changes, for miscellaneous circuit transfers, for intercepts, and the like. Second, it provides a free floating balanced force operation that was not previously available. Third, it provides for continuity testing of existing and future circuits. Fourth, it permits circuits to be switched to alternate paths of operation for checking prior to cutover. Fifth, switching circuitry may be provided on one or both sides of the cutover device. Sixth, a wiper action provides cleaning of the electrical contacts. Seventh, it may be used to provide any desired number of switching operations. Eighth, a positive step provides a holding action when this is deemed advisable. Ninth, accommodation of a rod permits simultaneous switching of a number of cutover devices. And finally, the disclosed cutover device provides improved, more reliable, longer-lived operation.

While the instant invention has been shown and described herein in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention.

What is claimed is:

1. In a slide switch assembly including a support means, fixed contact means mounted on said support means and movable cutover device contact means engaging said fixed contact means, the improvement in said movable cutover device contact means comprising:

a body having at least one generally rectangular recess of a given length, a given width, and a given depth;

a post centrally positioned in said recess;

the axial height of said post not being substantially greater than the depth of said recess;

a helical spring positioned to encircle said post;

said helical spring having a free length that is somewhat longer than the depth of said recess;

a generally bridge-shaped switching pad having a central contacting portion, a pair of sloping sides, and a pair of end tabs;

the overall length of said switching pad being slightly shorter than said given length of said recess;

the width of said switching pad being slightly smaller than the width of said recess;

said switching pad being positioned in said rectangular recess on said helical spring, with said end tabs oriented toward the bottom of said recess, and with said contacting portion oriented away from said bottom of said recess;

whereby said switching pad fits into said recess in a free-floating manner;

a cover strip having a generally rectangular cutout;

said cutout having a width that is substantially equal to said given width of said recess, and is slightly larger than the width of said contacting portion;

said cutout having a length that is somewhat longer than said contacting portion of said switching pad;

said cover strip being juxtaposed on said body with said cutout centered with respect to said recess of said body;

said contacting portion of said switching pad projecting through said recentangular cutout of said cover strip.

2. In a slide switch assembly including a support means, fixed contact means mounted on said support means and movable cutover device contact means engaging said fixed contact means, the improvement in said movable cutover device contact means comprisan elongated body "of insulation material having at least one generally rectangular recess therein of a given length in the longitudinal direction of the body, a given width, and a given depth;

retainer means of insulation material on said body and overlying the ends of said recess; a generally bridge-shaped switching pad of electrically conducting material having a raised central contacting portion, a pair of end tabs, and a pair of leg portions connecting the respective end tabs to said central contacting portion;

said switching pad being floatingly mounted in said recess, with said end tabs inwardly oriented toward the bottoms of the recess and underlying said retainer means, and said contacting portion outwardly oriented away from the bottom of said recess; and

spring means in said recess engaged generally centrally of said switching pad so as to bias said switching pad outwardly in a generally longitudinally balanced manner, with said central contacting portion of the switching pad exposed for contacting outwardly of said retainer means and with outward movement of the switching pad limited by engagement of said end tabs against said retainer means.

3. A cutover device contact means as defined in claim 2, wherein said retainer means comprises a cover strip mounted on said body and having a rectangular cutout through which said central contacting portion and said leg portions of said switching pad extend.

4. A cutover device contact means as defined in claim 2, wherein said spring means comprises a helical spring having its axial ends engaged, respectively, against the body at the bottom of said recess and against said central portion of said switching pad, said spring being centrally positioned between the longitudinal ends of said recess.

5. A cutover device contact means as defined in claim 4, which includes a post on the body extending upwardly from the bottom of said recess and centrally located between the longitudinal ends of said recess, said spring being centrally positioned by engagement of its inner axial end over said post.

6. A cutover device contact means as defined in claim 5, which includes outwardly projecting dimple means on said central contacting portion of the switching pad proximate the ends of said contacting portion and substantially equally spaced in said longitudinal direction from the axis of said spring for balanced contacting force. 

1. In a slide switch assembly including a support means, fixed contact means mounted on said support means and movable cutover device contact means engaging said fixed contact means, the improvement in said movable cutover device contact means comprising: a body having at least one generally rectangular recess of a given length, a given width, and a given depth; a post centrally positioned in said recess; the axial height of said post not being substantially greater than the depth of said recess; a helical spring positioned to encircle said post; said helical spring having a free length that is somewhat longer than the depth of said recess; a generally bridge-shaped switching pad having a central contacting portion, a pair of sloping sides, and a pair of end tabs; the overall length of said switching pad being slightly shorter than said given length of said recess; the width of said switching pad being slightly smaller than the width of said recess; said switching pad being positioned in said rectangular recess on said helical spring, with said end tabs oriented toward the bottom of said recess, and with said contacting portion oriented away from said bottom of said recess; whereby said switching pad fits into said recess in a freefloating manner; a cover strip having a generally rectangular cutout; said cutout having a width that is substantially equal to said given width of said recess, and is slightly larger than the width of said contacting portion; said cutout having a length that is somewhat longer than said contacting portion of said switching pad; said cover strip being juxtaposed on said body with said cutout centered with respect to said recess of said body; said contacting portion of said switching pad projecting through said recentangular cutout of said cover strip.
 2. In a slide switch assembly including a support means, fixed contact means mounted on said support means and movable cutover device contact means engaging said fixed contact means, the improvement in said movable cutover device contact means comprising: an elongated body of insulation material having at least one generally rectangular recess therein of a given length in the longitudinal direction of the body, a given width, and a given depth; retainer means of insulation material on said body and overlying the ends of said recess; a generally bridge-shaped switching pad of electrically conducting material having a raised central contacting portion, a pair of end tabs, and a pair of leg portions connecting the respective end tabs to said central contacting portion; said switching pad being floatingly mounted in said recess, with said end tabs inwardly oriented toward the bottoms of the recess and underlying said retainer means, and said contacting portion outwardly oriented away from the bottom of saiD recess; and spring means in said recess engaged generally centrally of said switching pad so as to bias said switching pad outwardly in a generally longitudinally balanced manner, with said central contacting portion of the switching pad exposed for contacting outwardly of said retainer means and with outward movement of the switching pad limited by engagement of said end tabs against said retainer means.
 3. A cutover device contact means as defined in claim 2, wherein said retainer means comprises a cover strip mounted on said body and having a rectangular cutout through which said central contacting portion and said leg portions of said switching pad extend.
 4. A cutover device contact means as defined in claim 2, wherein said spring means comprises a helical spring having its axial ends engaged, respectively, against the body at the bottom of said recess and against said central portion of said switching pad, said spring being centrally positioned between the longitudinal ends of said recess.
 5. A cutover device contact means as defined in claim 4, which includes a post on the body extending upwardly from the bottom of said recess and centrally located between the longitudinal ends of said recess, said spring being centrally positioned by engagement of its inner axial end over said post.
 6. A cutover device contact means as defined in claim 5, which includes outwardly projecting dimple means on said central contacting portion of the switching pad proximate the ends of said contacting portion and substantially equally spaced in said longitudinal direction from the axis of said spring for balanced contacting force. 